Between takes at the shrieking shack--a ghoulish, precariously quaking house on the fringes of the wizard village Hogsmeade--actor Daniel Radcliffe fiddles with his magic wand. Today's scene is a doozy: Harry Potter finally confronts the sinister (for now) Sirius Black. Over the screeching din of the shack, Radcliffe repeatedly shouts, "You betrayed my parents! You're the reason they're dead!" During a break in the action, though, he twirls his wand genially like a baton. Wait, sorry, it's not a baton--that'd be so 12 years old. Radcliffe, who turned 14 last week, is bashing the air feverishly. He's doing a drum solo.

To prepare for the older, bolder "Harry Potter and the Prisoner of Azkaban," Radcliffe has been listening to the Sex Pistols--which broke up 11 years before he was born--as well as edgy new acts like the Strokes and the Dandy Warhols. He's also watching Francois Truffaut ("The 400 Blows") and Vittorio De Sica ("The Bicycle Thief") to get a handle on Harry's "feelings of hopelessness." Yes, "Azkaban" is the puberty movie in the Potter franchise--the one, says Emma Watson, who plays Hermione, in which "all those lovely, lovely hormones start coming out." How will the movie reflect the changes afoot? "Lots of sex," says Alfonso Cuaron, the Mexican director who's taken over the reins of the series from Chris Columbus. "Lots of nudity. And lots of sex." Relax, he's joking. But Cuaron notes that his teenage cast is coming of age just as the characters are, and that there's, uh, pollen in the air. "You just have to let it flow," he says. "You don't need to encourage it. You allow it to be. And believe me, they have a lot of it." Watson, who's 13, has a sign on her dressing-room door that reads BEWARE: BABE INSIDE.

The first two Harry Potter films, "The Sorcerer's Stone" and "The Chamber of Secrets," both directed by the family-friendly Columbus, were earnestly mainstream affairs. Some critics shrugged, but each film grossed nearly $1 billion worldwide. Now, with the series' two lightest chapters out of the way, the stage is set for an adventurer like Cuaron, who got an Oscar nomination last year for the teen-sex romp "Y Tu Mama Tambien." By now, every fan of the franchise has torn through the thunderous new book, "The Order of the Phoenix," at least once, meaning the onus of keeping the insatiable Potter machine humming is about to shift back to Hollywood. Chronicling the erotic adventures of two Mexican teens might not seem like a job qualification for a Harry Potter movie, but hey, give Warner Brothers credit for showing some chutzpah. "Alfonso has a keen understanding of the nuances of teenage life," says producer David Heyman. " 'Y Tu Mama' is about the last moments of adolescence, and 'Azkaban' is about the first." Cuaron also directed the 1995 adaptation of the children's classic "A Little Princess," a film that had a great many fans, including a particularly vociferous one named J. K. Rowling.

Presiding over the "Azkaban" set in England's Hertfordshire countryside, the bearded, rumply-haired Cuaron cuts a entirely different figure than the all-American Columbus--and it's not just the mariachi music blasting during a midshoot celebration. "Alfonso is much more gritty than Chris ever was," says Watson. "He's really into the idea that [shooting] should be fluid and natural. People can be eating an apple during a take."

"Azkaban" is a spookier story than the first two--the soul-sucking dementors, who guard Azkaban Prison, make their first appearance--and Cuaron's design team promises that the movie's palette will reflect the gathering darkness. For Hogsmeade, set designer Stuart Craig labored to avoid a "pretty, chocolate-box" village, creating a main street that swerves zanily. Honeydukes, the candy store, is floor-to-ceiling psychedelia, with tangles of licorice and--a Cuaron touch--Mexican skulls made of sugar. (To prevent candy jars from magically emptying between takes, the cast has been told that the goodies are lacquer-coated. They're not.) Cuaron also reimagined the role of Professor Dumbledore after Richard Harris's death. British actor Michael Gambon now plays the Hogwarts headmaster as an elegant old hippie.

Cuaron's outspokenness is also new to the franchise. Does the evil wizard Voldemort still remind him of George W. Bush, as he said recently? "In combination with Saddam," he says. "They both have selfish interests and are very much in love with power. Also, a disregard for the environment. A love for manipulating people. I read books four and five, and Fudge"--Rowling's slippery Minister of Magic--"is similar to Tony Blair. He's the ultimate politician. He's in denial about many things. And everything is for the sake of his own persona, his own power. The way the Iraq thing was handled was not unlike the way Fudge handled affairs in book four." Cuaron's scrappiness is either refreshing or worrying, depending on your stock portfolio.

Of course, Cuaron doesn't have full run of the joint. Columbus, who says he was "too physically exhausted" to direct the third movie, is serving as producer--and he makes no bones about the fact that he's doing it to "protect" the Potter world he adores. Awkward as the arrangement sounds, both men insist it's working. Mostly, Columbus advises his successor on how to handle a job he describes as running a three-ring circus. Shooting is often interrupted by kids scampering off to do schoolwork. (Under British law, child actors can work only four hours a day.) While they're gone, Cuaron hops on his bicycle and rides to the editing room, where he readies shots for his visual-effects team. "The biggest pressure on Alfonso is delivering sequences to the effects people early enough," Columbus says. The effects in "The Sorcerer's Stone," Columbus concedes, "weren't up to snuff" because of time pressures. On the second film, he scheduled eight extra months to get them right. For "Azkaban," Cuaron's team has spent six months on the dementors alone.

Potter fans have grown used to a movie every Thanksgiving, but "Azkaban" will arrive in the teeth of the summer movie season on June 4, 2004. By then, the franchise could be in the midst of another creative shake-up. Radcliffe says he'll be riding the Nimbus 2000 in the fourth movie, "The Goblet of Fire," and it appears that his young costars, Watson and Rupert Grint, who plays Ron Weasley, will join him. Beyond that, they still have to ask Mom and Dad. "We're optimistic," producer Heyman says, "but it's early." As for Cuaron, his tour of duty in Harryland will end with "Azkaban." Whoever inherits the franchise next--Britain's Mike Newell ("Four Weddings and a Funeral") is on the shortlist--will get a nice signing bonus: Rowling's sequels have a knack for getting better.